1. Field of the Invention
The present invention generally relates to projection television receivers and particularly relates to a cooling system such in which a fluid is utilized for cooling a projection cathode ray tube in a projection television receiver.
2. Description of Problem To Be Solved
Referring to FIG. 1, a cooling system for a projection television receiver of the same inventor will be described.
In FIG. 1, a frame 22 includes a step portion 22a, and a projection face 28 of a projection cathode ray tube 21 is fixed through an adhesive agent 23 to the frame 22 at one side 30 of the step portion 22a. A lens 24 has a collar portion 24a which is mounted through a packing 25 on the frame 22 at the other side 31 of the step portion 22a. A pressing plate 26 is fixed to the frame 22 at its edge portion by screws 27. When the screws 27 are tightened, the lens 24 is urged against the packing 25 to seal the lens to the frame 22 at the step portion 22a. The space defined between the projection face 28 of the projection cathode ray tube 21 and the lens 24 is filled with cooling liquid A.
In a structure such as that described above, it is necessary to provide the packing 25 to seal the cooling liquid A in the space between the projection face 28 of the projection cathode ray tube 21 and the lens 24. Silicon rubber has been used with some success as the material of the packing 25. However, silicon rubber is easily permeable to the passage of gas therethrough. Thus, when the cooling liquid is heated by heat generated by the projection cathode ray tube 21, the vapor may pass through the packing 25, and the quantity of the cooling liquid is gradually dissipated. Thus, a picture may be partly cut off unless the cooling liquid is supplemented at regular periods.
Accordingly, it is a primary object of the invention to seal a projection-type television receiver for preventing the loss of cooling liquid therefrom.
It is another object of the present invention to provide a cooling system for a projection television receiver in which a sealing member such as a packing is made of a material which does not allow passage of a gas therethrough, so that if cooling water is heated to generate vapor, the vapor is retained, and a stable picture can be maintained for a long period of time.